代码随想录算法训练营day49 121.买卖股票的最佳时机 122.买卖股票的最佳时机||

题目链接121.买卖股票的最佳时机

class Solution {
    public int maxProfit(int[] prices) {
        if(prices == null || prices.length == 0){
            return 0;
        }
        int len = prices.length;
        int[][] dp = new int[len][2];
        dp[0][0] = -prices[0];
        dp[0][1] = 0;
        for(int i = 1; i < len; i++){
            dp[i][0] = Math.max(dp[i-1][0], -prices[i]);
            dp[i][1] = Math.max(dp[i-1][1], dp[i-1][0] + prices[i]);
        }
        return dp[len-1][1];
    }
}

题目链接122.买卖股票的最佳时机||

class Solution {
    public int maxProfit(int[] prices) {
        if(prices == null || prices.length == 0){
            return 0;
        }
        int len = prices.length;
        int[][] dp = new int[len][2];
        dp[0][0] = -prices[0];
        dp[0][1] = 0;
        for(int i = 1; i < len; i++){
            dp[i][0] = Math.max(dp[i-1][0], dp[i-1][1]-prices[i]);
            dp[i][1] = Math.max(dp[i-1][1], dp[i-1][0] + prices[i]);
        }
        return dp[len-1][1];
    }
}